Wendy Treynor - Are the Most Mistrustful the Least Trustworthy? Studies of Unethical Behavior
2006-10-09 00:00 (America/Los_Angeles)
Wendy Treynor: USC Institute for Creative TechnologiesIs one who believes that unethical activity is common unlikely to act ethically? To test the hypothesis that cynical beliefs predict unethical behaviors, actual unethical activity was examined by developing two laboratory techniques. In the American History Aptitude Test cheating technique, participants were told they would be rewarded with 10 cents for each question on a test that â€œaccidentallyâ€ had the correct answers already marked on it, whereas in the Weight Perception Task stealing technique, participants estimated the weight of objects using coins from a bowl, which they sat alone with, containing $71.00 of coins. Regardless of technique used, cynicismâ€”the belief that
others are engaging in unethical acts or that unethical behavior is common or normalâ€”was found to positively predict unethical behavior.

Andreas Wilke - The adaptive problem of finding resources
2006-10-16 00:00
Andreas Wilke: UCLA Department of AnthropologyWhen resources are distributed in patches animals must decide when to switch from a depleted patch. The optimal policy is given by the Marginal Value Theorem, which has successfully predicted animal behaviors, but as a mechanism it becomes problematic when each patch contains few discrete prey items. Biologists have proposed simple alternative decision mechanisms and calculated in which environments each works well. We tested whether the decision mechanisms evolved to direct animals when to leave a food patch also underlie human decision making in the same context, and whether humans in an internal-search task (e.g. information in memory) use the same mechanisms as in an external-search task (e.g. physical objects).

Colin Camerer - Status, ethnicity, and wealth in Vietnam: Evidence from experimental games
2006-10-23 00:00
Colin Camerer: CalTech Department of Business EconomicsWe conducted economic experiments to investigate interethnic discrimination with the members of three ethnic groups, i.e., Vietnamese, Khmer and Chinese, in southern Vietnam. Vietnamese are the major ethnic group, and Khmer and Chinese are main minority groups. Chinese are the richest and Khmer are the poorest among the three ethnic groups.
We found that 1) Khmer (poor minority) show the strongest solidarity. 2) Vietnamese (majority) do not show solidarity when they are matched with Khmer (poor minority), but demonstrate ingroup bias when they are matched with Chinese (rich minority). 3) Vietnamese often comply with the social norm of fair allocations, choosing equal splits both in Dictator Game and Third Party Punishment Game. 4) Khmer send much more in Third party Punishment game than in Dictator Game, while Chinese reduce the amount sent when the third party is introduced (crowing-out effects). 4) Both minorities punish Vietnamese more severely when Vietnamese violate the norm. 5) Both minorities protect ingroup victims more than they do outgroup victims.

Mark Changizi - Letters from nature
2006-10-30 00:00
Mark Changizi: CalTech Sloan-Swartz Center for Theoretical NeurobiologyReading pervades every aspect of our daily lives, so much so that one would be hardpressed to find a room in a modern house without words written somewhere inside. Many of us now read more sentences in a day than we listen to. Not only are we highly competent readers, but our brains even appear to have regions devoted to recognizing words. A Martian just beginning to study us humans might be excused for concluding that we had evolved to read. But, of course, we havenâ€™t. Reading and writing is a recent human invention, going back only several thousand years, and much more recently for many parts of the world. We are reading using the eyes and brains of our illiterate ancestors. Why are we so good at such an unnatural act? Here I describe new evidence that, although we have not evolved to be good at reading, writing appears to have culturally evolved to be good for the eye. More specifically, new research supports the hypothesis that human visual signs look like nature, because that is what we have evolved over millions of years to be good at seeing. This ecological hypothesis for letter shape not only helps explain why we are such good readers, but answers the question, Why are letters and other visual signs shaped the way they are?http://www.bec.ucla.edu/papers/Changizi_10.30.06.pdf

Paul Bloom - Bodies and Souls
2006-11-06 00:00
Paul Bloom: Yale Department of PsychologyHow do we think about bodies and souls? Findings from developmental psychology suggest that both children and adults see physical entities such as objects (or bodies) as fundamentally distinct from psychological entities such as minds (or souls). We are natural-born dualists. Our dualism explains why we are so drawn to certain religious beliefs — such as life after death and the existence of supernatural entities — and it also underlies certain aspects of moral reasoning.

Michael Cannon - Modeling the Tradeoff between Foraging and Farming
2006-11-13 00:00
Michael Cannon: CSU Long Beach Department of AnthropologySome archaeologists have used a model of optimal time allocation from human behavioral ecology to help explain variability over space and time in the importance of farming vs. foraging. I discuss a model that builds on this previous work in an effort to enable a more detailed understanding of the factors relevant to the development of prehistoric agriculture. This model is more explicit about the activities involved in agriculture, modeling the costs and benefits of harvest-producing activities and post-harvest processing activities separately; this potentially provides a means for integrating labor division into the model. The model also enables a consideration of the roles that both mean productive efficiency and variability in production might play in the evolution of agricultural economies. Model predictions are evaluated against archaeological data from the American Southwest to clarify the factors that underlay increases in the importance of agriculture in this region.

Joan Silk - The origins of prosocial preferences
2006-11-20 00:00
Joan Silk: UCLA Department of AnthropologyHumans differ from most other animals, and from virtually all other primates, in the extent of our dependence on cooperation. In humans, altruism seems to be at least partly based on empathy and genuine concern for the welfare of others (Batson and Powell 1998; Fehr and Fischbacher 2003). We may also be motivated by a concern for reputation (Haley and Fessler 2005), that makes us want others to think that we are generous, fair, or charitable. Nonhuman primates also act altruistically, but the extent and deployment of altruism in primate groups is much more limited than it is in human societies. Altruistic interactions usually involve very small numbers of individuals (usually dyads) and is strongly biased by kinship. There is some evidence for reciprocity among unrelated individuals, but these exchanges are generally restricted to short-term exchanges of low-cost commodities. It is not clear what limits altruism in nonhuman primate groups. New work suggests, however, that differences in the deployment of altruism in human and nonhuman primate may be linked to differences in the capacity for empathy, the existence of moral sentiments, and the concern for the welfare of others.

Peter Richerson - The Role of Religion in Human Cooperation: Experiments Using Economic Games
2006-11-27 00:00
Peter Richerson: UC Davis Department of Environmental Science and PolicyReligion is often held to play a large, even dominant, role in supporting human cooperation. Much variation in propensities to cooperate and treat others fairly exists within and between human societies. Previous work by social psychologists suggested that religion plays a small role in explaining this variation, but the validity of the dependent variables used is questionable. We used behavior in Dictator, Trust, and Public Goods games as dependent variables to test for the effects of a wide variety of measures of religious participation, experiences, beliefs, and affiliation on cooperation and other prosocial behaviors. Despite the data-dredging aspects of our experimental design, we found significant effects of religious variables on prosocial behavior. Further, various dimensions of religiosity correlated with game behavior in a way that is somewhat consistent with findings from the experiments devised by social psychologists. However, we found little evidence an “ingroup” effect; participants did not send more money to individuals with similar religious preferences. By comparing numerous models using an information-theoretical approach, we draw some general conclusions about which theories are data are most likely to support.

Dario Maestripieri - Biological bases of caregiver attachment
2006-12-04 00:00
Dario Maestripieri: University of Chicago Department of Comparative Human DevelopmentIn human and nonhuman primates, caregiver attachment is a motivational/ behavioral system that promotes the maintenance of proximity between a caregiver and an infant and facilitates the expression of caregiving behavior. Comparative data on female interest in infant and infant-directed behavior in nonhuman primates and humans will be used to illustrate the proximate regulation, development, adaptive function, and evolution of the caregiver attachment system.

Rob Boyd - Reciprocity is not sufficient to explain human cooperation
2007-01-08 00:00
Rob Boyd: UCLA Department of AnthropologyRecent discussions of human cooperation assume that the theory reciprocal altruism provides an established explanation for human cooperation, and that therefore, alternative explanations invoking cultural group selection face a burden of proof. In this talk, I argue that this assumption is not justified. The theory of reciprocal altruism does predict that cooperative behavior among small groups of unrelated individuals will evolve, but this theory is not supported by most empirical data. The theory of reciprocal altruism also predicts that cooperative behavior is evolutionarily stable, but also predicts that any other behavior is equally likely to be stable, and thus does not provide a sufficient explanation for the commonness of large scale human cooperation. I also argue that the theory of cultural group selection is cogent, and consistent with much empirical data.

Wendy Saltzman - Endocrinology of Female Reproductive Competition in Cooperatively Breeding Marmoset Monkeys
2007-01-22 00:00
Wendy Saltzman: UC Riverside Department of BiologyCommon marmosets are cooperatively breeding monkeys that exhibit high female reproductive skew: typically only a single, dominant female breeds successfully in each social group. Laboratory studies have indicated that reproductive suppression in subordinate females is not aggressively imposed on them by dominant females and is not associated with stress; instead, it is mediated by a specific, presumably adaptive neuroendocrine mechanism. Moreover, subordinate females readily begin to breed under favorable conditions, such as following introduction of an unrelated male into the group, and show no impairments in their ability to maintain pregnancy or successfully produce offspring. When two females breed concurrently, however, they engage in overt reproductive competition, with pregnant females commonly killing one anotherâ€™s infants. In sum, our findings are consistent with recent manipulation-based models of reproductive skew, in which reproductive suppression in non-breeders is mediated, mechanistically, by self-restraint but has evolved in response to selection â€“ namely, infanticide â€“ imposed by breeding females.http://www.bec.ucla.edu/papers/Saltzman_1.22.07.pdf

Alex Mesoudi - Towards a unified science of cultural evolution: A brief theoretical background and some experimental examples
2007-02-05 00:00
Alex Mesoudi: University of British Columbia W. Maurice Young Centre for Applied EthicsA Darwinian theory of cultural evolution holds that the same fundamental principles that govern biological change â€“ variation, selection and inheritance â€“ also underlie human cultural change. In fact, the empirical case for cultural evolution is now as strong as the case that Charles Darwin presented in The Origin of Species for biological evolution (Mesoudi, Whiten & Laland, 2004). Consequently, similar tools, methods and theories that biologists use to study biological evolution can be adapted to study cultural change, and the structure of the science of biological evolution â€“ evolutionary biology â€“ can serve as a model for the structure of a science of cultural evolution (Mesoudi, Whiten & Laland, 2006).
One branch of this science of cultural evolution is the experimental study of cultural transmission, which uses the methods of social psychology to identify systematic biases that affect the transmission of information through groups of people. For example, Mesoudi, Whiten and Dunbar (2006) found that information regarding social relationships is transmitted with greater fidelity than equivalent non-social information, consistent with â€œMachiavellian intelligenceâ€ hypotheses of primate brain evolution. Mesoudi and Oâ€™Brien (submitted), meanwhile, simulated the cultural transmission of arrowhead designs, matching different transmission biases to actual patterns of prehistoric arrowhead variation in the archaeological record. This integration of individual-level transmission biases and population-level archaeological patterns is facilitated by an evolutionary approach to human culture.http://www.bec.ucla.edu/papers/Mesoudi_2.5.07.pdf

Pascal Boyer - Why do patients and religious people perform rituals?
2007-02-12 00:00
Pascal Boyer: Washington University Department of PsychologyRitualized behavior is found in children’s typical development, as well as in the pathology of OCD and in cultural ceremonies. Pierrre Lienard and I proposed elsewhere a neurocognitive model of ritualized behavior in human development and pathology, as based on the activation of a specific hazard-precaution system specialized in the detection of and response to potential threats. I argue that certain features of collective ritualsâ€¹by conveying information about potential danger and presenting appropriate reaction as a sequence of rigidly described precautionary measuresâ€¹probably activate this neurocognitive system. This makes some collective ritual sequences highly attention-demanding and intuitively compelling and contributes to their transmission from place to place or generation to generation.

Karl Sigmund - Between freedom and enforcement: public goods and costly punishment
2007-02-15 00:00
Karl Sigmund: University of Vienna Department of MathematicsA considerable body of theoretical and empirical evidence underlines the important role of punishment in stabilising high contributions to joint enterprises. But how does punishing behaviour emerge? This talk highlights the role of voluntary participation. Analytical methods and individual-based simulations show that social norms including the punishment of exploiters can emerge more easily if it is possible to abstain from the joint enterprise.

Susan Carey - The Origin of Concepts: The Case of Natural Number
2007-02-26 00:00
Susan Carey: Harvard Department of PsychologyI make two non-controversial assumptions about human conceptual understanding. First, it is built from a shared set of developmental primitives–the representational resources bequeathed to all human beings by evolution. Equally obviously, human cultures create new representational resources, transcending these initial ones in format, content and expressive power, which are turn internalized by individuals in the course of conceptual development. These assumptions, even if granted, leave open radically different possibilities concerning the processes of conceptual development and the scope for cross-cultural variation. How rich are the developmental primitives? How constraining of adult cognition are they? Does human conceptual development require transcending the initial state, and if so, what mechanisms make this possible? .
I will illustrate an empirical research program addressing this space of theoretical options in the domain of numerical cognition, focusing on the developmental primitives with numerical content, the cultural construction of integer representations, and the bootstrapping processes that allow each child to transcend their initial representational resources, creating representations of natural number.

Bernard Comrie - Vertical and horizontal transmission of language structure
2007-03-05 00:00
Bernard Comrie: Max Planck Institute for Evolutionary Anthropology Department of Linguistics & UC Santa Barbara Department of LinguisticsAn understanding of the transmission of language across time requires reference to both vertical transmission – for instance, the English word “father” is a direct inheritance from the ancestral language Proto-Indo-European – and horizontal transmission – “paternal” was taken from Latin in the medieval period. This applies not only to vocabulary but also to language structure (grammar). The recently completed project The World Atlas of Language Structures (www.wals.info) for the first time provides the possibility of investigating such relations in detail. The talk will refer specifically to structural features that seem more amenable to either vertical or horizontal transmission, and include discussion of linguistic areas like Southeast Asia that result from widespread horizontal transmission and of the kinds of historical signals that can be detected in comparing structural information from languages of sub-Saharan Africa.

Brenda Bowser - Learning and Transmission of Pottery Style: Women's Life Histories and Communities of Practice in the Ecuadorian Amazon
2007-03-12 00:00
Brenda Bowser: Cal State Fullerton Department of AnthropologyThis paper examines the transmission of stylistic behavior in the community of Conambo. The people of Conambo are self-sufficient horticultural foragers who are strongly divided into two competing coalitions with flexible membership and defections across the coalitional boundary. The women of Conambo maintain a domestic polychrome ceramic tradition absent from external market influences. Previous studies show that pottery design in Conambo is understood and used strategically as a marker of group membership. In this paper we report age and status differences in perception and transmission of stylistic behavior, indicating that women’s pottery style and strategies of signification track life-history changes in their political relationships with in-group and out-group allies. We argue that in Conambo the transmission of ceramic design is influenced by the political strategies of women throughout their lives.

Daniel J. Kruger - Sexual selection, male competition, and sex differences in human mortality rates
2007-03-19 00:00
Daniel J. Kruger: University of Michigan School of Public HealthSex differences in human mortality rates stem from genetic, physiological, behavioral, and social causes that are best understood when integrated in an evolutionary life history framework. Males in many species are selected for riskier physiological and behavioral strategies that enhance reproductive success at the expense of health and longevity. Sex differences shaped by sexual selection interact with the environment to yield a pattern with some consistency, but also with expected variations due to socioeconomic and other factors. This presentation investigates the notion that sex differences in human mortality rates are related to levels of male competition for resources, social status, and mates, and that the actual or potential degree of skew in resource control will influence the degree of male competition and excess male mortality.http://www.bec.ucla.edu/papers/Kruger_3.19.07.pdf

Paul Griffiths - The Baldwin effect and genetic assimilation
2007-04-02 00:00
Paul Griffiths: University of Queensland Department of PhilosophyMany evolutionary processes have been described in which a trait that initially develops in the members of a population as a result of some interaction with the environment comes to develop without that interaction in their descendants. Waddingtonâ€™s genetic assimilation is importantly different from the rest of this â€˜Baldwinianaâ€™ because his explanatory focus was not on the selection pressures at the point of transition, but on how developmental systems come to be structured in such a way that these evolutionary transitions are readily accessible to evolving lineages. Waddingtonâ€™s approach also replaces the simple contrast between â€˜acquiredâ€™ and â€˜innateâ€™ with a non-dichotomous model of developmental canalisation and phenotypic plasticity that is in line with recent work on the evolution of development. From a Waddingtonian perspective evolutionary transitions between â€˜innateâ€™ and â€˜acquiredâ€™ are only to be expected because those categories have little meaning in terms of developmental genetics and in some cases the difference between the â€˜innateâ€™ and â€˜acquiredâ€™ may require only a minimal change in developmental mechanisms. But to see this it is necessary to use a gene concept suitable for thinking about development, and not a gene concept designed for theoretical population genetics or for the prediction of phenotypic differences within populations.http://www.bec.ucla.edu/papers/Griffiths_2.4.07.doc

Hillard Kaplan - The human adaptive complex and the evolution of the 70 year lifespan
2007-04-09 00:00
Hillard Kaplan: University of New Mexico Department of AnthropologyThis paper will present an overview of age-specific mortality rates among hunter-gatherers and forager-horticulturalists. It will also present new data on resource transfers and physical rates of aging among Tsimane forager-horticulturalists in Bolivia. It will be argued that the balance of costs and benefits of maintenance and repair of the human soma have resulted in a modal adult age at death of 70 or so years. Seven decades of life may be considered the evolved species-typical lifespan of Homo sapiens.

Caitlin O'Connell-Rodwell - The Importance of Communication and Culture to the African Elephant
2007-04-16 00:00
Caitlin O’Connell-Rodwell: Stanford University Department of Otolaryngology, Head and Neck SurgeryThe structure of African elephant society is primarily matriarchal in nature, where dominant female elephants make decisions for the herd as a whole with regard to safety, movements, resource choices and affiliations. Culture is often influenced by local environmental and social pressures, as well as the character of individual herd members. Aspects of elephant society that contribute to survival will be discussed in the context of mechanisms that elephants employ to communicate over long distances. In addition, new findings about elephant bull society will be reviewed, highlighting the importance of bonding and mentoring adolescent delinquent males.http://www.bec.ucla.edu/papers/OConnellRodwell_4.16.07.pdf

Joan Silk - Sex Ratio: Local Resource Competition and Local Resource Enhancement
2007-04-23 00:00
Joan Silk: UCLA Department of Anthropology

Nicola S. Clayton - Memories of Tomorrow: Do Animals Remember the Past and Plan for the Future?
2007-04-25 00:00
Nicola S. Clayton: University of Cambridge Department of Experimental PsychologyAccording to the mental time travel hypothesis only humans can mentally dissociate themselves from the present, travelling backwards in time to recollect specific past events about what happened where and when (episodic memory) and travelling forwards in time to anticipate future needs (future planning). Studies on the behaviour of food-caching western scrub-jays question this assumption. In terms of retrospective cognition, these birds remember the ‘what, where and when’ of specific past caching episodes, they keep track of how long ago they cached different types of perishable foods that decay at different rates, and also remember whether another individual was present at the time of caching, and if so, which bird was watching when. Recent work demonstrates that the jays also make provision for a future need, caching more food in places in which they will not be given breakfast the next morning than in places where they will be receive breakfast the next morning even though there is plenty of food available to them when they cache the food. Taken together these results challenge the mental time travel hypothesis by showing that some elements of both retrospective and prospective mental time travel appear not to be uniquely human.http://www.bec.ucla.edu/papers/Clayton_4.25.07a.pdf

James Roney - Preliminary data testing an alternative explanation for menstrual phase effects on women's mate preferences
2007-04-30 00:00
James Roney: UC Santa Barbara Department of PsychologyMenstrual cycle shifts in women’s mate preferences have generally been interpreted as products of adaptations designed to alter behavior during the fertile window relative to other times in the cycle. I will discuss an alternative theory that posits that such shifts may be produced by mechanisms designed to use ovarian hormone concentrations to calibrate behaviors across different menstrual cycles. I will then present preliminary data showing that women’s estradiol concentrations correlate positively with their preferences for facial cues of men’s testosterone concentrations, and that this relationship holds during times of the cycle that are outside the fertile window. These data do not argue definitively for either position but do at least suggest the plausibility of the between-cycle alternative explanation.

Janet Sinsheimer - Family Feuds: Maternal-Fetal Genotype Incompatibility
2007-05-07 00:00
Janet Sinsheimer: UCLA Departments of Human Genetics, Biomathematics and BiostatisticsBiological mechanisms involving a combination of genetic and environmental factors have been hypothesized to explain susceptibility to complex familial
disease. I will present our efforts to detect interactions between mother’s and child’s genes that may create adverse prenatal environments and increase susceptibility to diseases such as schizophrenia and rheumatoid arthritis.http://www.bec.ucla.edu/papers/Sinsheimer_5.7.07a.pdf

Carl Lipo - Resolution of the Cultural Phylogenies of Monumental Statues on Easter Island
2007-05-14 00:00
Carl Lipo: CSU Long Beach Department of AnthropologyThe monumental statues (moai) of Easter Island represent substantial investment in cultural elaboration by the prehistoric islanders. Constructing explanations of these features requires generating measurements of temporal and spatial statue variability. Using a method based in cultural transmission, cladistics and occurrence seriation I present the results of analysis that potentially reflects a phylogeny of the monumental statues. This work enables the evaluation of models of statue change in which diversity of styles and materials produces patterns of lineages and the general form of an explanatory model for the evolution of culture elaboration on this famous island.

Stacey Rucas - Allies and Rivals: The Complex world of women's social dynamics among the Tsimane of Bolivia
2007-05-21 00:00
Stacey Rucas: California Polytechnic State University Department of Social SciencesThis research examines the complexity of women’s social behaviors with other women through various modes of evolutionary inquiry and methods. Results indicate that women engage in alternating forms of competitive and cooperative behaviors across the lifecourse in their quest for reproductively limiting resources. Data presented will highlight several avenues of research conducted with the Tsimane that attempt to identify contested resources, track their exchanges, and understand the use of social aggression to secure status and compete (or cooperate) for friends, mates and food within female social networks.

Alison Gopnik - Causal maps and Bayes nets: Causal inference and theory formation in children, scientists and computers
2007-06-04 00:00
Alison Gopnik: UC Berkeley Department of PsychologyHow do we accurately infer the causal structure of the world around us? Thirty years of developmental research has shown that human children form and revise intuitive theories of everyday physics, biology and psychology. These theories are similar to the formal theories of science. Recent work in philosophy of science, computer science and statistics has developed formal computational models of this kind of theory formation, particularly in the framework of causal graphical models or Bayes nets. Iâ€™ll argue that we can think of intuitive theories as causal maps, analogous to the spatial maps animals use in navigation. These maps allow us to consider counterfactual alternatives, design complex plans and act to change our environments, and they may be uniquely human. I will present evidence showing that preschool children construct such maps in ways that accord with the Bayes net formalism.http://www.bec.ucla.edu/papers/Gopnik_4.6.07.pdf

Hanna Kokko - Love and hatred in a world of feedback
2007-08-07 00:00
Hanna Kokko: University of Helsinki Department of Biological and Environmental SciencesI will present results on both `loveÂ´ (sexual selection) and `hatredÂ´ (territorial conflict). In both cases I will investigate the role of `feedbackÂ´, that is, ask the question how strongly individual behaviour influences population dynamics, which then feeds back to influence what is adaptive at the individual level. We know that selection does not favour what is good for a group (or species), but do we ask often enough how `badÂ´ it can get? For example, are sexually selected species expected to be particularly prone to extinction? And, does territoriality in the Seychelles magpie robin (that only this year got its status lifted from critically endangered to endangered) increase its vulnerability to environmental change?http://www.bec.ucla.edu/papers/Kokko_1.29.07.pdf

Mark Kleiman - Maximizing cooperation while minimizing punishment
2007-10-01 00:00
Mark Kleiman: UCLA Department of Public PolicyThe threat of punishment can facilitate cooperation by discouraging defection and aggression. Because punishment is scarce, costly, and painful, optimal enforcement strategies will minimize the amount of actual punishment required to effectuate deterrence. If potential offenders are deterrable, increasing the conditional probability of punishment (given violation) can reduce the amount of punishment actually inflicted, by “tipping” a situation from its high-violation equilibrium to its low-violation equilibrium. Compared to random or “equal opportunity” enforcement, dynamically concentrated sanctions can reduce the punishment level necessary to tip the system.http://www.bec.ucla.edu/kleimanpaper.doc
